I am looking at white brothers pipe E- SERIES, K&n jet kit and air filter. Does anybody have this set up. I am also looking into the WB rev kit I am not familiar with a rev kit is it worth the $100 bucks and does it put more strane on the engine because of the higher rpm. Does anybody know the proper jetting for this, White brothers said 158 and no adjustment with the needle and K&N said they are wrong. They said to jet up to 178 and change the needle due to the area I ride which is NJ. Who is right. Also imput on the throttle adjustment it was talked about in another forum, how do you check to see if you are getting full responce. Thanks for the help.

 

I do not own a WB E-series for my 400ex instead, I have an FMF Powercore 4 S/A. I am very pleased with the performance however, the E-series has gotten excellent reviews as well. I also have a K and N powerkit installed on my machine too. Both components increased horsepower and torgue tremendously. Just to let you know, I have also heard the the WB rev kit is a bad idea for the 400ex. Sources say that it does strain the engine although, you get an extra 1000 rpms. A way to get around that is, I have heard but I am not for sure, but a rev box off of an old 250r will work on a 400ex. I don't know how, but someone said that it is capable. I would talk to your dealer, or an expert mechanic before doing so.

As for rejetting, I know nothing about that. I had a professional mechanic rejet my 400ex. I would also talk to your dealer or a four stroke mechanic on that issue. Sorry, I am not that much help for your question, but I would definately stay away from the WB rev kit. What I would do is install the pipe, filter, and jet kit (to your preferred jetting) and then go out and run the crap out of it. If it tends to "boug-out" at high rpm's, you are either burning to rich or too lean. I would install those three things and ride it and then make the decision if it is worth the extra 1000rpm's from the WB rev kit. Just remember, putting a exhaust system, and air filter with a jet kit isn't really that risky at all in my opionion. But when you start screwing with anything more than that you are kissing the reliability factor. Yeah, everyone eventually wants to go bigger and faster. But there does come a point to reliability and stupidity. Sure I will admitt, I would like to have a 440 kit. But I am not sure if I want to take the risk of breaking anything internally. You understand? I'm not trying to talk you out of anything, (except for the WB rev kit) but I am just giving you a word of advise. Thanks.

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